Japanese Patent Application Publication No. 2014-61984 discloses an image recording apparatus that can record an image on each side of a recording medium such as a recording sheet. According to the disclosed apparatus, after a recording sheet is supplied from a sheet supply tray, an image is recorded on a front surface of the recording sheet by a recording portion while the recording sheet is conveyed in a conveying direction by a first conveying roller. The recording sheet on which the image has been recorded is then conveyed to a second conveying roller positioned downstream of the recording portion in the conveying direction. The second conveying roller, with its rotation in a forward direction, conveys the recording sheet to a discharge tray. Further, the second conveying roller, with its rotation in a reverse direction, can convey the recording sheet to a reverse conveying passage through a branch opening formed between the recording portion and the second conveying roller. The recording sheet that has been conveyed to the reverse conveying passage is conveyed to a portion upstream of the recording portion in the conveying direction. Subsequently, in a manner the same as the image recording on the front surface, an image is recorded on a back surface of the recording sheet while the same is conveyed by the first conveying roller. The recording sheet subjected to double-sided recording (i.e., double-sided printing) is then discharged to the discharge tray by the second conveying roller.
Further, it has been known in the art that a “simultaneous process” is performed in a conventional image recording apparatus. That is, in a case where the conventional apparatus performs double-sided recording to a plurality of recording sheets, the conventional apparatus conveys a preceding sheet in which an image has been recorded on a front surface to the reverse conveying passage by the second conveying roller while conveying a subsequent recording sheet in the conveying direction by the first conveying roller. With such simultaneous process, conveyance of the preceding sheet to the reverse conveying passage by the second conveying roller and conveyance of the subsequent sheet by the first conveying roller can be simultaneously performed. Accordingly, double-sided recording can be performed at high speed.